Ornamental coating and process of making same



l ntented Feb. 9, "1932 UNITED STATES PATENT OFFICE ll. PEARL, OF "WINDSOR, 'VlERlVIONT, AElSIGIN'OR TO LABORATOIRES SEVIGNE- lPl Lltl'tlL, Illl'tt, 'UF "WINDSOR, VERMONT, A CORCPURATION 01E VERMONT tllfil l'fillllllhl'tllhll GOATING- AND PRUClEfiQ OF MAKING- QAMIE Ztt'o brewing. Application filed May it,

lln my application, Serial No. 120,196, filed duly 2, 1926, l have described ornamental coatings made or cellulose derivatives, such nitrocellulose or other materials, hereintcr specifically enumerated and a method making such coatings. In accordance the method therein described, nitrocelulose and a suitable crystallizable compound, uch as monobrom camphor, sublnnable or orizable below the decomposition temature o'l nitrocellulose, are dissolved in U per proportion in a common solvent, to-

ether,i't desired vvith acolorantsuch as a dye. ..he solution is applied as a thin coating to suitable surface or base, such as paper, and are solvent is permitted to evaporate, pretrably under controlled temperature c0ndi oi Upon evaporation of the solvent, the sets and the crystallizable compound ystallizes "Within and throughout the ent re coating. The coated product is then. heated. to about the subliming temperature of the crystals therewithin, causing them to be :leased and enpelled and leaving behind in aglio in the coating their natural design or contigiu'ation. it coating thus made, al- "hough composed of nitrocellulose, presents .emarlrable appearance and makes possible production oi many beautit'ul etlects, es ecially "when crystallizable compounds ming needle crystals are employed. 'lhere arecertain disadvantages inherent he step of heating the product to expel the crystals, it long period at heating is necesy to produce the desired intaglio efiect ttl t consequently, although the coating of material, such as paper, may be cared out rapidly by a continuous process and 1e evaporation oil the solvent and crystaltion takes place quickly, the rate or protuction is limited by such long heating cried, and the use oi cumbersome and en- ]ensive itestooning apparatus tor supporting the coated paper, during such heating is also necessary. The paper is also liable to acquire a pronounced curl during heating, which is diltlcult to remove. Furthermore, the crystalline effect must be obtained by the use oil? a crystallizable compound readily valtll pcrisable or sublimable below-the decomposirttt il: at

rear. serial No. tenets.

tion temperature or the nitrocellulose. Monobrom campnor satisfies this requirement and produces a highly attractive crystalline effect, but it is expensive and has a camphor odor which it is ditlicult to remove from the paper even by long heating and ageing, and which is obyectionable when the paper is to be employed for the manufacture of candy boxes or the like.

' l have now discovered that it after crystallization has taken place, the coated product is treated for a suthcient period Wither material which exerts a pronounced solvent action upon the crystal but Which does not appreciably attack the nitrocellulose, sumcient crystal may be dissolved and removed from the coating to producea crystalline intaglio ell ect comparable to that obtained/by heating. 'lhis discovery hence makes possible the successful use of certain odorless crystalline compounds, such as salicylic acid, which are materially less expensive than monobrom camphor but Which, owing to their lower volatility, cannot be expelled easily by the action of heat and ageing.

The step of removing the crystal may be accomplished very rapidly by the use oil such a solvent, and a much higher rate oi? produc--- tion is possible in carrying out a continuous coating operation, as on paper, and Without the use or expensive, cumbersome apparatus for carrying out such a step. Thus, the coated paper need only be passed through a bath of the solvent for a :t'evv minutes to dissolve sutlicient crystal to produce the desired crystalline intaglio eil'ect. Since the crystal may be odorless, only that portion of the crystal readily accessible to the solvent need heremoved to produce the desired eilect.

Another phase of my invention relates to lift till

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crystallization in the coating material has been efi ected, into Water-soluble reaction products, so that Water may be emplo ed as the solvent medium, thereby greatly re ucing the cost of practising my process. When ll employ crystallizable compounds such as salicyclic acid, which are comparatively insoluble in water but which are neutralizable, their neutralization may be eflected to form Waterlull soluble salts with solutions of suitable alkalies, as hereinafter described.

The method of the present invention may be practised as by following a procedure substantially as follows. About'12 pounds of nitrocotton and about ounds of salicyclic acid are dissolved in sufhcient common solvent to roduce a coating composition having a speci 'c gravity of about .95 to .96. If desired, a dye or other colorant may be added jtQ the solution. Preferably, the solvent is of the proper Volatility to produce good crystalline growth at about room temperature, say, at about 60 to 7 5 F. Various volatile solvents may be employed for such purpose, such, for example,as a mixture consisting of to 4c7% acetone, 45% to 4.7% ethyl acetate, and 5% to 10% butyl alcohol. The com position may be applied to paper and the solvent permitted to evaporate at about to 85 F. After crystallization is complete, the coated product-is passed through a bath of a I suitable salicyclic acid solvent, e. g., an aqueous solution of sodium borate or sodium phosphate. Solution of the salicyclic acid occurs because of its neutralization by the alkaline sodium compounds to form sodium salicylate,

- which is' far more soluble in water thansalicylic acid. Thus, whereas only .27 grams of salic lic acid dissolves in 100 cc. of water at 29 about 111 grams of sodium salicylate dissolves in 700. cc. of ,water at 15 C. -A warm, saturated solution is preferably employed to producea rapid rate of crystal solution. Theproduct need be kept in the solution for only a few minutes, to dissolve sufiicient crystal to produce a satisfactory effect comparable to that produced b heating a coated product for a long perio at elevated temperature. In place of an aqueous solution of salts, other salicylic acid solvents may be employed, such as glycerine, ethyl or methyl alcohol, diluted, with 10% to 20% water so as not to attack the nitrocellulose, or a mixtureof benzol and methyl alcohol.

Where a crystal such as salicylic acid,

: which is fairly soluble in water, is employed,

\ the passage of live steam through the paper for a suflicient period of time has been found to remove suflicient crystal to produce a satisfactory efiect. It is my opinion that the com bined solvent and heating action of thesteam results in a steam distillation or sublimation of the salicylic acid.

A method such as hereinbefore described, may also be applied successfully in ornamentally coating wood, celluloid, leather, fabric,

or other cellulosic or organic materials which may be subject to injury by heat. In the case of wood, it may be desirable to carry the process further. Thus, after the coating has-been applied to the wood and allowed to set, it is washed with a salicylic acid solvent such as borax solution or benzol suflicient not only to dissolve the salicylic acid crystals from the coating and produce a crystalline intaglio therein, but to strike through the coating to the wood and dissolve a certain amount of resin and natural gum from thesurface of the wood, particularly when the wood is resinous, such as pine. Thisacc'entuates the grain of the wood and adds to the beauty of the product. The coating is then preferably covered with a protective coating, e. g., a water soluble gum such as gum arabic or linseed oil, then preferably rubbed down, and finally surface-finished with a glazedmparting material such as varnish or shellac. In the case of leather, the salicylic acid solvent which I preferablyemploy is glycerine, or a mixture of glycerine and water, for not only is glycerine a good salicylic acid solvent but it does no injury to the'leather as other solvents, such as volatile solvents, might.

In lieu of'salicylic acid, I may employ ben- 'zoic acid, or other relatively volatile, ineX- pensive, and preferably odorless crystalline compound which preferably forms needle crystals and which may be dissolved from the coating in sulticient amount to produce a satisfactory effect. 111 lieu of nitrocellulose, I may employ any equivalent thereof, e. g., a gum orwax which will form a coacting or film and which is soluble in some solvent in which the crystal-forming substance may be dissolved; A similar effect is produced as with nitrocellulose, through it may lack something of the beautiful appearance inci dent to the use of nitrocellulose.

Having thus described this invention, it is obvious that it is capable of various changes and modifications without departing from its spirit or scope as defined by the appended claims.

What I claim is:

1. A process which comprises applying a solution comprising salicylic acid and nitrocellulose to a base material, allowing the solvent to evaporate to cause a setting of the nitrocellulose and a crystallization of the acid therein, and treating the product with an aqueous solution of borax.

2.' A process which comprises applying to a base material a volatile solvent solution of a water-insoluble coating material and a crystallizable compound comparatively insoluble in water, allowing the solvent to evaporate to cause a setting of the coating and a crystallization of the compound therein reacting upon the compound without appre ciably attacking the coating material to produce a water-soluble reaction roduct, and dissolving the reaction product in an aqueous medium. i

3. A process which comprises applying to a base mntcriaht volatile solvent solution of a water-insoluble coating material and-a crystallizable compound comparatively insoluble in water but neutralizable to produce awater-soluble reaction product, allowing the llll solvent to evaporate to cause a setting of the coating and a crystallization of the compound therein, neutralizing the compound to produce a water-soluble reaction product, and dissolving the reaction product in an aqueous medium.

l. A process which comprises applying to a lease material a volatile solvent solution of a water-insoluble coating material and an acid crystallizable compound comparatively insoluble in water, allowing the solvent to evaporate to cause a setting of the coating and a crystallization of the compound therein, and treating the roduct with an aqueous solution of alkali to orm a water-soluble salt.

5. A process which com rises applying to a lease a volatile solvent so ution of a waterinsoluhle coating material and salicylic acid, allowing the solvent to evaporate to cause a setting of the coating and a crystallization of the salicylic acid, and treating the product with an aqueous solution of alkali to form a water-soluble alkali salicylate.

' 6. A process which comprises applying to a lease a volatile solvent solution of a waterinsoluble coating material and salicylic acid, allowing the solvent to evaporate to cause a setting of the coating and a crystallization of the salicylic acid, and treating the product with an aqueous solution of alkaline sodium compounds to form sodium salicylate.

7. A process which comprises coating paper with a volatile solvent solution of nitrocellulose and salicylic acid, evaporating the solvent present in the coating to cause a setting of the nitrocellulose and a c stallization of the salicylic acid therein, an then immersing the coated paper in an aqueous alkaline solution to dissolve crystallized salicylic acid from the coating.

In testimony whereof I have afiixed my signature.

AZARIAH Y. PEARL. 

